border-1px($color){
	position:relative;
	&:after{
	   display:block;
	   position: absolute;
	   left: 0;
	   bottom: 0;
	   width: 100%;
	   border-top: 1px solid $color;
	   content: '';
	}
}
border-none(){
	&:after{
		display: none;
	}
}
bg-image($url){
	background-image:url($url+"@2x.png");
	@media (-webkit-min-device-pixel-ratio:3),
	(min-device-pixel-ratio:3){
		background-image:url($url+"@3x.png");
	}
}